Tuesday, July 19, 2011

SPARKFUN Clockit Kit Review

Overall this is a great kit for beginners there are a couple of really good hits and a couple of misses

The first and biggest miss is the DC power connector doesn't fit right! it's way off I mesured about 6.53mm O.D. a huge difference in size of the 5.5mm O.D. plug, producing a very sloppy connection (see video n1ir.com) and would cut power as soon as I move the PCB even the slightest.

I replaced the original jack with a Switchcraft 5.5mm X 2.5 mm Jack (RAPC712X). I have a solid connection now without problems, hopefully sparkfun will look into this and change the jack to the proper size.

The second miss but can easy be changed with programming is setting the time, there is allot of switch bounce (one press can register as 2 or more presses), It's annoying but I can live with it. With a simple subroutine for advanced users can fix this.

The third miss WTF? display is used ????? It's stamped YS on the side. After doing some research I crossed it over to a Lite-On (LTC-4627B) the crossed part has a grey face instead of the black that comes with the kit but still blue in color. Please add this info in web site.

Big Hit I really like the PWM of the display LED's that reduced the parts count. It's a very clever, a novel solution to reduce parts. Usually you see current limit resistors for each segment this would be 35 resistors in this design, by using PWM it eliminated the need and reduced the cost of the design, excellent idea!

Big Hit Bright flash when going into set mode, to set the time. Three flashes to know it's been accepted.

Big Hit ICSP Header, can be reprogrammed in circuit as a timer or modified. Wish they had some more example code on the kit web site.

Big Hit comes with a power supply, usually kits don't included this, A++.

SIP connector PCB pads for +/- supply for battery backup (hardware solution, optional NI-CD cell/ super-cap in paralleled with supply) just for a few minutes of backup for any surges or power outage. Possible sleep mode while in backup (hard to do without a redesign....need an open port and support circuitry)